Renal response status to predict long-term renal survival in patients with lupus nephritis: results from the Toronto Lupus Cohort.

Objective: To evaluate modified versions of the Belimumab International Study in Lupus Nephritis (BLISS-LN) belimumab study primary efficacy renal response (mPERR) and complete renal response (mCRR) criteria (excluding mandatory corticosteroid tapering) as predictors of real-world, long-term renal outcomes among patients with lupus nephritis (LN).

Methods: This retrospective, observational study (GSK Study 212866) used deidentified data between 1970 and 2015 from the University of Toronto Lupus Cohort from adults diagnosed with systemic lupus erythematosus and biopsy-proven Class III±V, IV±V or V LN. At 24 months postbiopsy, patients were retrospectively indexed as responders/non-responders based on mPERR (estimated glomerular filtration rate (eGFR) ≤20% below biopsy value/≥60 mL/min/1.73 m and urine protein:creatinine ratio (uPCR) ≤0.7 g/day) or mCRR (eGFR ≤10% below biopsy value/≥90 mL/min/1.73 m and uPCR ≤0.5 g/day) criteria. The association between index mPERR (primary outcome) or mCRR (secondary outcome) status and long-term (up to 25 years, until censoring or death) renal survival (no progression to end-stage kidney disease (eGFR <30 mL/min/1.73 m, dialysis or transplant) or death) was assessed.

Results: Overall, 179 patients were included in the analysis (mPERR responders, n=128; non-mPERR responders, n=51). Most patients were female (87.2%); the mean (SD) age was 34.1 (11.3) years.Long-term renal survival was attained for 78.9% of mPERR responders and 60.8% of non-mPERR responders; achieving mPERR was associated with an increased likelihood of long-term renal survival versus not achieving mPERR (log-rank p=0.0119). Overall, 102 patients were mCRR responders, and 77 were non-mCRR responders. Long-term renal survival was attained for 80.4% of mCRR responders and 64.9% of non-mCRR responders; achieving mCRR was associated with an increased likelihood of long-term renal survival than not achieving mCRR (log-rank p=0.0259).

Conclusions: Achieving mPERR or mCRR was associated with improved long-term renal survival, highlighting that these statuses are suitable predictors of long-term renal outcomes in patients with LN.